Vertical transmission of maternal DNA through extracellular vesicles associates with altered embryo bioenergetics during the periconception period

Role of neuroglia cell-derived microvesicles in cobalt chloride-induced mitochondrial autophagy in neurons

The extensive use of cobalt resources has significantly increased the risk of cobalt contamination globally, with cobalt chloride posing a serious environmental and health concern. Although previous studies have shown that extracellular vesicles play a key role in intercellular communication, the mechanisms by which extracellular vesicles derived from neuroglia cells affect neuronal cells remain poorly understood. This study aimed to investigate whether microvesicles produced by neuroglia cells could mitigate cobalt chloride-induced neuronal damage and to explore the underlying mechanisms. Our results revealed that cobalt chloride induces cytotoxicity in HT22 and MN9D neuronal cells. A 24-hour cobalt chloride treatment triggered mitochondrial autophagy in both cell types and disrupted their mitochondrial dynamics. Further analysis showed that microvesicles secreted by GL261 neuroglia cells were taken up by both types of neuronal cells. Notably, the uptake of GL261-derived microvesicles by MN9D cells inhibited autophagy and restored mitochondrial membrane potential and reactive oxygen species levels. In conclusion, our findings highlight the critical role of neuroglia cell-derived microvesicles in cobalt chloride-induced neuronal toxicity and offer potential new targets and strategies for the prevention and treatment of cobalt chloride toxicity.

Endometrial Aging and Reproductive Decline: The Central Role of Mitochondrial Dysfunction

Socioeconomic factors have led an increasing number of women to postpone childbirth, thereby elevating the risks of reduced fertility, pregnancy complications, preterm birth, cesarean delivery, and chromosomal abnormalities. While diminished oocyte quality is a well-established contributor to age-related infertility, endometrial dysfunction also plays a pivotal role. Optimizing both oocyte quality and endometrial health is essential for enhancing reproductive outcomes. Although aging has been defined by twelve hallmarks, research specifically addressing age-related changes in endometrial function remains limited. This review examines the process of endometrial aging, with a particular emphasis on mitochondrial function. A comprehensive literature search was conducted using PubMed and Google Scholar to identify relevant studies published up to 31 January 2025. Endometrial aging is driven by multiple biological mechanisms, most notably the decline in endometrial receptivity. Key contributing factors include hormonal dysregulation, chronic inflammation, cell cycle arrest, genomic instability, epigenetic alterations, telomere attrition, and mitochondrial dysfunction. Among these, mitochondrial dysfunction emerges as a central driver of the aging process. Endometrial senescence, precipitated by irreversible mitochondrial impairment, may underlie the progressive decline in reproductive potential. Elucidating the role of mitochondrial dysfunction in aging provides critical insights into the molecular basis of fertility decline, particularly through its impact on endometrial receptivity.

Tracking Small Extracellular Vesicles Using a Minimally Invasive PicoGreen Labeling Strategy

Extracellular vesicles (EVs) are cell-secreted lipid bilayer delimited particles that mediate cellular communication. These tiny sacs of cellular information play an important role in cell communication and alter the physiological process under both normal and pathological conditions. As such, tracking EVs can provide valuable information regarding the basic understanding of cell communication, the onset of early malignancy, and biomarker discovery. Most of the current EV-tracking strategies are invasive, altering the natural characteristics of EVs by modifying the lipid bilayer with lipophilic dyes or surface proteins with fluorescent reporters. The invasive labeling strategies could alter the natural processes of EVs and thereby have major limitations for functional studies. Here, we report an alternative minimally invasive EV labeling strategy using PicoGreen (PG), a small molecule that fluoresces at 520 nm when bound to dsDNA. We show that PG binds to dsDNA associated with small EVs (50-200 nm), forming a stable and highly fluorescent PG-DNA complex in EVs (PG-EVs). In both 2D cell culture and 3D organoid models, PG-EV showed efficient tracking properties, including a high signal-to-noise ratio, time- and concentration-dependent uptake, and the ability to traverse a 3D environment. We further validated PG-EV tracking using dual-labeled EVs following two orthogonal labeling strategies: (1) Bioconjugation via surface amine labeling and (2) donor cell engineering via endogenously expressing mCherry-tetraspanin (CD9/CD63/CD81) reporter proteins. Our study has shown the feasibility of using PG-EV as an effective EV tracking strategy that can be applied for studying the functional role of EVs across multiple model systems.

Mitochondrial Extracellular Vesicles (mitoEVs): Emerging mediators of cell-to-cell communication in health, aging and age-related diseases

Mitochondria are metabolic and signalling hubs that integrate a plethora of interconnected processes to maintain cell homeostasis. They are also dormant mediators of inflammation and cell death, and with aging damages affecting mitochondria gradually accumulate, resulting in the manifestation of age-associated disorders. In addition to coordinate multiple intracellular functions, mitochondria mediate intercellular and inter-organ cross talk in different physiological and stress conditions. To fulfil this task, mitochondrial signalling has evolved distinct and complex conventional and unconventional routes of horizontal/vertical mitochondrial transfer. In this regard, great interest has been focused on the ability of extracellular vesicles (EVs), such as exosomes and microvesicles, to carry selected mitochondrial cargoes to target cells, in response to internal and external cues. Over the past years, the field of mitochondrial EVs (mitoEVs) has grown exponentially, revealing unexpected heterogeneity of these structures associated with an ever-expanding mitochondrial function, though the full extent of the underlying mechanisms is far from being elucidated. Therefore, emerging subsets of EVs encompass exophers, migrasomes, mitophers, mitovesicles, and mitolysosomes that can act locally or over long-distances to restore mitochondrial homeostasis and cell functionality, or to amplify disease. This review provides a comprehensive overview of our current understanding of the biology and trafficking of MitoEVs in different physiological and pathological conditions. Additionally, a specific focus on the role of mitoEVs in aging and the onset and progression of different age-related diseases is discussed.

The detection, biological function, and liquid biopsy application of extracellular vesicle-associated DNA

Cell-derived extracellular vesicles (EVs), which carry diverse biomolecules such as nucleic acids, proteins, metabolites, and lipids reflecting their cell of origin, are released under both physiological and pathological conditions. EVs have been demonstrated to mediate cell-to-cell communication and serve as biomarkers. EV-associated DNA (EV-DNA) comprises genomic and mitochondrial DNA (i.e., gDNA and mtDNA) fragments. Some studies have revealed that EV-DNA can represent the full nuclear genome and mitochondrial genome of parental cells. Furthermore, DNA fragments loaded into EVs are stable and can be transferred to recipient cells to regulate their biological functions. In this review, we summarized and discussed EV-DNA research advances with an emphasis on EV-DNA detection at the population-EV and single-EV levels, gene transfer-associated biological functions, and clinical applications as biomarkers for disease liquid biopsy. We hope that this review will provide potential directions or guidance for future EV-DNA investigations.

Endometrial Proliferative Phase-Centered View of Transcriptome Dynamics across the Menstrual Cycle

The endometrium, the inner mucosal lining of the uterus, undergoes complex molecular and cellular changes across the menstrual cycle in preparation for embryo implantation. Transcriptome-wide analyses have mainly been utilized to study endometrial receptivity, the prerequisite for successful implantation, with most studies, so far, comparing the endometrial transcriptomes between (i) secretory and proliferative endometrium or (ii) mid-secretory and early secretory endometrium. In the current study, we provide a complete transcriptome description of the endometrium across the entire menstrual cycle and, for the first time, comprehensively characterize the proliferative phase of the endometrium. Our temporal transcriptome analysis includes five time points including the mid-proliferative, late proliferative (peri-ovulatory phase), early secretory, mid-secretory, and late secretory phases. Thus, we unveil exhaustively the transitions between the consecutive proliferative and secretory phases, highlighting their unique gene expression profiles and possible distinct biological functions. The transcriptome analysis reveals many differentially expressed genes (DEGs) across the menstrual cycle, most of which are phase-specific. As an example of coordinated gene activity, the expression profile of histone-encoding genes within the HIST cluster on chromosome 6 shows an increase in cluster activity during the late proliferative and a decline during the mid-secretory phase. Moreover, numerous DEGs are shared among all phases. In conclusion, in the current study, we delineate the endometrial proliferative phase-centered view of transcriptome dynamics across the menstrual cycle. Our data analysis highlights significant transcriptomic and functional changes occurring during the late proliferative phase-an essential transition point from the proliferative phase to the secretory phase. Future studies should explore how the biology of the late proliferative phase endometrium impacts the achievement of mid-secretory endometrial receptivity or contributes to molecular aberrations leading to embryo implantation failure.